Woodstock is finally as old as it looks. The 400,000 or so kids who congregated on Max Yasgur's farm 40 years ago this weekend have, with this anniversary, achieved a quiet and happy state of AARPifact. "Woodstock: Now & Then," a sweet and fascinating co-production of VH1 and the History Channel, is appropriately filled with the sort of peace and love that comes with wrinkles, veneered teeth (Wavy Gravy -- still alive! -- wears a rainbow-hued upper bridge) and a moseying, but not plodding, pace.

It's nice to see. Nick and Bobbi Ercoline, "the couple in the blanket" from the Woodstock album cover, are still married. Nicest of all is that the bragging and cultural superiority of that generation has calmed; the hippies seen here all turned into lovely, twinkly eyed senior citizens and just want you to come in, sit (eat!) and talk. Country Joe McDonald, who helped Woodstock's crowd spell out the f-word over and over again, reminds me of an algebra teacher who just took retirement.

Certainly the Woodstock generation has done a terrific -- the Gen-X sourpuss in me would hasten to add "annoying" -- job of reminding those of who weren't there what a major moment we missed. (I was in diapers, 2,000 miles away, no doubt acting impulsively in a whole other style of nearly naked freakout; what's your excuse?) You had to be there is a constant refrain, and as easy to tune out as it is to turn on.

But in the hands of Oscar-winning documentarian Barbara Kopple, the patronizing tone of previous retrospectives has abated, and the three-day music festival overtakes the 1969 lunar landing in terms of sheer wonder. Where it seems possible to me that Americans could still do the math and build the rockets to return ourselves to the moon, "Woodstock: Now & Then" (which airs Friday at 9 p.m. on VH1) is saturated with the wistful, if largely unspoken, certainty that there will never in our lifetimes be another Woodstock.

A concluding montage of President Obama's inauguration aims to connect the dots back to those three days in August, and it's this production's only misstep. Our 21st-century massings and messages are simply too manipulated, too self-conscious and too hyperlinked to compare. My favorite part is about the pay-phone bank at the festival, where kids lined up to phone family and friends, an old-fashioned Twitter dispatch, to assure their parents that everything was groovy.

I did not expect to be moved by the historical feel this time around, since Jimi Hendrix's version of the "Star-Spangled Banner" is seared as permanently into my mental archive as yours or anyone else's with YouTube access. It's easy, after all this time, for Woodstock to feel like homework. Michael Lang, one of the original four promoters -- and an executive producer of this special -- walks us once more through the miraculous occurrences of good fortune that saved the festival. The logistics, and the fact that 400,000 people got along in what was essentially a disaster area of dopey disarray, will always be the prevailing narrative of Woodstock. Co-promoters Artie Kornfeld and Joel Rosenman are on hand for reminiscences of the chaos and joy; John P. Roberts, the young pharmaceutical heir who bankrolled the concert, died in 2001, and appears in footage from a prior interview.

Another thought, watching this: From farmer Yasgur (a Republican who believed strongly in the rights of young people to convene and defied his neighbors to give them space), to the four young men who planned to put on the concert, to many of the performers, to Abbie Hoffman's rabble-rousing, to a large number of the attendees who are interviewed in "Woodstock: Now & Then," the festival seems to have been, in the subtlest of ways, a triumph of Jewish American ingenuity. Woodstock preached the universality of humankind, with not even three decades between it and the Holocaust -- a shorter distance than now exists between Woodstock and us. This documentary doesn't have the time or space to delve into such sociological tangents, and, anyhow, the festival will forever be fused with the Vietnam War.

Yet, as the Woodstockers have aged into anyone's ideal of cute Florida grandparents and history's timeline compresses, I wonder if Woodstock won't ultimately be seen as a life-affirming epilogue to the worst horrors of the 20th century.

From here on, as Woodstock turns 50 and then 60, more of its participants will be gone. So watch closely, respectfully, this time, as the same old lentil soup is spooned out in a new way. This is the first Woodstock anything I've seen that bothers to check in with, and relate to, the generations who came after. We spend a considerable amount of time at a "school of rock" for children, where the adorable D'Addario brothers, Michael and Brian, launch into a raucous cover of the Who's "My Generation." It's like Woodstock is saying goodbye.

The always enjoyable footage of crowds and performances comes from news archives and from the hit 1970 documentary film (which turned out to save the investors' hides). It's not new, but I found myself once again stunned by Woodstock's innocence:

Not a single corporate logo in sight.

Woodstock: Now & Then (two hours) airs Friday at 9 p.m. on VH1 and again Monday at 8 p.m. on the History Channel.